Apparatus and method for applying indexing strips to cable pair groups

ABSTRACT

This application describes apparatus for placing thin complaint strips at intervals crosswise over a group of advancing twisted wire pairs. The two wires of each pair thread through separate threadways in a lockable rotor. As the twisted pairs advance in unison, the respective rotors turn at rates differing with the various pair twist lengths. The rotors are locked at different times, but each in a position that conforms all threadways in a single plane. The strips are then applied downstream of the rotors, where by then the wires lie flat. Thereafter, the rotors are unlocked.

United States Patent TO POWER SOURCE JAW ACTUATOR 72] inventor Tillman Gressitt [56] References Cited 1 N ggghgagllle, Md. UNITED STATES PATENTS [21] P 2,564,874 8/1951 Andren 29/630 [22] Filed Sept. 12,1969

2,708,459 5/1955 Andren etal.. 140/1 22525:: mil 'l je zrie Laboratories Incorpor t d 3,177,566 4/1965 Hester 29/203H 9 Murray HmmL 3,363,309 1/1968 Logan et a1. 29/203DTX Primary ExaminerGranville Y. Custer, Jr. Attorney-R. J. Guenther ABSTRACT: This application describes apparatus for placing thin complaint strips at intervals crosswise over a group of ad- [54] vancing twisted wire pairs. The two wires of each pair thread Cl 10 D through separate threadways in a lockable rotor. As the rawmg twisted pairs advance in unison, the respective rotors turn at [52] U.S. Cl 29/630, rates differing with the various pair twist lengths. The rotors 29/203 are locked at different times, but each in a position that con- [51] Int. Cl HOlr 6/00 forms all threadways in a single plane. The strips are then ap- [50] Field of Search 29/203 plied downstream of the rotors, where by then the wires lie flat. Thereafter, the rotors are unlocked.

PATENTED W25 IBYI SHEET 1 [1F 5 JAW UATOR CYCLE CONTROL TO POWER SOURCE JAW ACTUATOR INVENTOR 7.1!. GRESS/TT ,4 T TORNE V PATENTEU NAY25 ism saw u [If 5 APPARATUS AND METHOD FOR APPLYING INDEXING STRIPS TO CABLE PAIR GROUPS FIELD OF THE INVENTION This invention relates to the manufacture of multipair communications cable, and in particular concerns apparatus and method for applying indexing strips.

RELATED APPLICATIONS FOR LETTERS PATENT In the US. Pat. No. 3,459,878 of T. J. Gressitt et al. issued Aug. 5, I969 and assigned to applicants assignee, there is described a-scheme for greatly simplifying pair identification for a multipair subscriber cable. The scheme concurrently maintains particular pairs in predetermined spaced relation to aid in their tennination to special indexing strips and connector blocks of the type described in the patent application of B. C. Ellis, Ser. No. 787,453 filed Dec. 27, 1968, and assigned to applicants assignee.

The invention described below concerns the preparation of conductor groups with indexing strips for such a structure.

BACKGROUND OF THE INVENTION The manufacture of multipair cable typically begins, as is well known, with making up of pairs of insulated conductors twisted together to various pitch lengths. Several pairs, for example, five, then are brought together in a strand which is the building block of multipair cable.

In order for the'indexing strips to be placed across the conductors of a given strand so that they are maintained periodically in a predetermined and spaced sequence, the aforementioned procedure requires adaptation.

Further requirements include a minimum of disruption to the twist configuration designed into each pair, and the maintenance of correct tip-ring layout at the indexing strip point, without sacrifice of continuous strand fabrication or of speed.

Accordingly, the main inventive objects are:

to mechanize the preparation of strand units for indexed cable; to produce indexed cable without disturbing the process continuity or the designed twist configurations;

to accommodate any random set of twist lengths in applying indexing tapes; and

to bring at repeated intervals the several conductors into a predetermined, space relationship.

SUMMARY OF THE INVENTION Pursuant to the invention, the tip and ring wires of conductor pairs twisted in situ are thereafter threaded through separate tip and ring threadways in a lockable rotor. As the twisted pairs advance in unison, the respective rotors turn freely at rates differing with the various pair twist lengths. To apply a strip, the rotors are locked at different times with each at a final position that brings the threadways into a single plane. The strips are then applied downstream of the rotors and on either side of the conductors. Thereafter, the rotors are unlocked.

In one aspect, the invention includes locking pins for each rotor. The pin of each rotor is advanced to lock position a full twist length ahead of lockup, thus to assure that within that distance the rotor will arrive at lockup. The initiation of this lockup occurs at different times for each twist length; and all rotors are eventually brought to lockup.

The conductors are drawn continuously through the rotors during lockup, at a uniform linear velocity. The conductors emerge parallel and equally spaced with respect to one another. A momentary pileup of twists on the upstream side of the rotor is dissipated when, after application of the index strip, the rotors are released. The backed-up twists are then free to spin through and catch up to an unstrained position. In the latter aspect then, the invention avoids accumulation of significant deviation in the pattern of twists originally imparted.

Parallelism of the conductors emerging from the locked rotors is maintained, pursuant to another aspect of the invention, by a comb which is inserted between the moving conductors and drawn a short distance downstream.

. The tapes, advantageously, are heat-sealable plastics such as polyester-polyolefin film laminates a segment of which is positioned on either side of the array. After combout, the tapes are suitably pressed together and fused, thereby capturing the moving conductors in the desired spaced sequence.

One feature of the invention thus is a means of continuously tracking the tip and ring of each pair, and on command ordering the pair into the specified sense.

An added inventive feature is a comb for keeping separated conductors momentarily parallel prior to taping.

A further feature of the invention is the use of orificed rotors which during their free running permit any twist length to flow through them without disarrangement, but which can all be linearly ordered within the time it takes for the longest twist length to complete a cycle.

The invention and its further objects, features, and advantages will be fully apprehended from a reading of the description to follow of a detailed illustrative embodiment.

DESCRIPTION OF THE DRAWING FIG. I is a schematic perspective diagram of an entire system embodying the invention;

FIG. 2 is a frontal perspective view of the rotors and mount- FIG. 3 is a frontal perspective view of a rotor and its locking p FIGS. 4-9 are schematic side perspective views of the rotor comb and tape application sequences; and

FIG. 10 is a front perspective view of a conductor group with index strip applie ILLUSTRATIVE EMBODIMENT- First, by way of general description, the invention and its environment may be understood with reference to FIG. 1. Shown there is a source 1 of twisted pairs 2, 3, 4, 5, 6. Pair source I can be a plurality of reels of pairs twisted to desired twist lengths; or alternatively, can be one of numerous available pair-twisting mechanisms which twist the pairs at location from reels of insulated conductors. Twisted pairs 2-6 are drawnthrough an indexer 7, and then through a tape application station 8, where the indexing strips are periodically applied. Thereafter, pairs 2-6 are fed around a pulley 9 onto a store reel 10 which is turned constantly by a motor 11.

The pairs 2-6 have differing twist lengths and thus, since they are all advanced by motor 11 at the same rate, will each take varying times to trace out a full twist. Indexer 7 in its operation takes account of this condition in detwisting the pairs 2-6 at intervals without permanently removing any twist.

As shown in FIG. 2, indexer 7 consists of a block 12 rigidly mounted to a surface, not shown. Five rotors l3, l4, l5, 16, 17 are mounted in the block with their axes in a plane perpendicular to the major face. Each of the rotors 13-17, as shown in FIG. 3, is a cylinder with two threadways l8, l9 symmetrically placed about the cylinder axis. A ramp 20 is cut into the side of each cylinder which ends abruptly at a stop 21. The plane of stop 21 bears a known relation to the location of threadways I8, 19. In the FIG. 3 illustration, the stop 21 of each rotor 13-17 falls in a plane that is perpendicular to the plane described by the axes of the two threadways l8, l9, and intersects the latter plane midway between the axes. A lock pin 22 mounted in block 12 for sliding movement toward and away from rotor 13 when actuated, engages the stop 21, to stop rotation of rotor 13.

It will be understood that each of the rotors 13-17 is constructed with a ramp 20, a stop 21, and a lock pin 22. The rotors 13-17 are each mounted, for example, on precision bearings, not shown, for low friction rotational movement in blockl2. Lock pins 22 advantageously include a spring section 23 which, when the lock pin is thrust forward to the engaging position, enables the lock pin to ride down the ramp I 20.

FIG. 2 also illustrates the condition that when the rotors l3- --l7 are all locked, the threadways l8, 19 of each rotor are placed in a single plane. V

In FIG. 4, the twisted pairs 26 are shown feeding through the respective rotors 13-17 of indexer 7. In setting up the machine initially, the tip wire of each pair 26 is threaded through the threadway 18 of the respective rotors 13l7. The ring wire of each pair 26 is threaded through the threadway 19 of the respective rotors 13,l7. At the beginning of a cycle as the pairs are drawn through indexer 7, the rotors 13-17 are not engaged by the lock pins 22, and hence the rotors rotate freely at various rates. As illustrated in FIG. 4, the threadway 18, 19 or rotors l3-l7 are rather randomly oriented with respect to each other.

- Downstream from indexer 7 is the tape applicator station 8 I consisting of opposed jaws 24, 25 disposed on opposite sides of the wire array. Jaws 24, 25 are moved, in the direction of arrows 26, by suitable actuators 27 which can, for example be air pistons. Jaws 24, 25 are equipped with teeth 28, which, when the jaws are brought in contact, mate or touch at their crowns. The teeth of each jaw are separated by about the same distance that exists between the wiresas they emerge from in-- dexer 7, once the rotors arelocked. Included in each jaw 24, 25 is a heat source such as a coil 57 connected to an energy source, not shown, by wires 58.

Wire separation is maintained by a comb 31 variously positioned by a comb actuator 42. Plastic strips 35, 36 are periodically fed from a suitable source such as reel 30, to either side of the advancing wire array. The strips are severed from their source, for example, by tape cutter 38, or any other suitable device including shears that are commonly used for such purpose.

The cycle sequence is advantageously governed by acycle control 50. In FIG. 1, cycle control 50 is connected to the actuators 27 and their heaters 57 by the circuits 51; to the lock pin actuator 29 by the circuit 52; to the tape cutter and assembly 38 by the circuit 53; to the motor 61 of tape source 30 by the circuit 54; to the comb actuator 42 by the circuit 55; and to the reel motor 11 by the circuit 56. These connections, as set forth in FIG. 1, can be electrical, hydraulic, pneumatic or purely mechanical. Those shown merely broadly illustrate the automation of the inventive process and are not intended to serve as limitations thereon, it being obvious that numerous equivalent items of apparatus and control expedients can be enlisted to the same purposes.

OPERATION Locking of the rotors commences the sequence for tape application and is achieved by. actuator 29 responding to a signal from cycle control 50. Lock pins 22, in response are thrust forward until each is engaged on the stop 21 of the respective rotors. Jaws 24, 25 at this point are separated as in FIG. 4. With rotors l3 17 locked, the conductors of the pairs 26 commence to lose their twist as illustrated in FIG. 5. This twist temporarily builds up' behind the rotors. The conductors emerge in spaced, parallel relation and with the same tip-ring sense.

The separation soon progresses downstream to comb 31. The teeth 32 of comb 31 are formed to engage between the wires of each pair 26 to render all wires more nearly parallel. This is achieved as illustrated in FIG. 6 by advancement of comb 31 first in the direction of arrow 33. Immediately thereafter, as illustrated in FIG. 7, comb 31 is drawn downstream in the direction of arrow 34. Concurrently, two strips 35, 36 of plastic tape are advanced by the tape position actuator 61 from source 30 preparatory to application on the wires.

The jaws 24, 25 then are extended to heat bond together the two strips 35, 36 from opposite sides of the wire array. Then, in rapid succession the strips 35, 36 are severed by the tape cutter 37. As shown in FIG. 8, withdrawal of comb 31 in the direction of arrow 39 is begun. Comb 31 then is moved forward in the direction of arrow 40, FIG. 9, to its position as originally shown in FIGS. 4 and 5.

The plastic tapes 35, 36 now fon'n an indexing strip across the wires of the pairs 26. Directly after severing of the tapes, the lock pins are withdrawn, releasing the rotors 1317 for free rotation. The twists which until this time were backed up behind indexer 7, now quickly catch up by virtue of their forcing themselves, in efiect, through their respective rotors. FIG. 9 illustrates that the twists, present on each of the pairs 2-6,

have advanced to the index strip just applied. The store reel is in practice much larger than is shown in FIG. 1; and placement of the indexed wire group thereon may be aided by various well-known expedients such as a stranding lay or twist imparted to the whole group by rolling the reel about its axis parallel to the incident wire group.

The invention thus has sorted out the tip and ring wires of a number of twisted pairs, placed them in a known and spaced sequence, and fixed them thus with an indexing strip, as illustrated in FIG. 10. The tip and ring sense of this configuration is achieved by the tab 41 which is formed at the tip side of the configuration.

The spirit of the invention is embraced in the scope of the claims to follow.

I claim:

1. Method for periodically maintaining dissociated threadlike elements in spaced, parallel sequential relation comprising the steps of:

drawing subgroups of said elements through respective linear passages in plural rotatably mounted members capable of being lockably positioned to render all said passages planar and parallel;

momentarily locking said elements while continuing with said drawing;

maintaining said elements planar and parallel for a short distance at their point of emergence from said passages;

adhering a flexible strip to all conductors at said point; and

unlocking said members.

2. Method for periodically maintaining all conductors of a group of insulated and variously twisted conductor pairs in spaced, parallel sequential relation comprising the steps of:

drawing the conductors of each pair through separate passage pairs in each of a plurality of rotors freely rotatable and capable of being lockably positioned to render all said passages planar, parallel, and of predetermined spacmg;

momentarily locking said rotors while continuing drawing said conductors therethrough;

maintaining said conductors planar, parallel and so spaced for a short distance beyond their point of emergence from said passages;

fastening a flexible strip to all conductors at said point; and

unlocking said members.

3. Method of claim 2 wherein said fastening step comprises adhering first and second strips to each other with said conductors sandwiched thereinbetween.

4. Method of claim 2 further comprising completing said locking step within the time required for the pair with the longest twist length to complete one revolution.

5. Apparatus for periodically applying flexible strips to conductors in a group of twisted pairs comprising:

a plurality of freely rotatably mounted rotors for threadably receiving each of the conductors of the respective twisted pairs;

means for locking each rotor to orient all threaded conductors in a single plane;

- means for momentarily extending the conductor portions in spaced, parallel relation and for thereafter applying a flexible strip crosswise at such point; and

means for releasing each rotor for resumption of free rotation.

6. Apparatus for periodically applying flexible strips to tipring telephone conductors in a group of twisted pairs, characterized by:

a pluralityof freely rotatable rotors each with two threadways for receiving the respective conductors of a given pair, a one of each said threadings designated to receive the tip conductor of the given pair;

means for drawing the conductors of each pair through said rotors while freely rotating;

means for locking said rotors in threadways planar and parallel while continuing to draw said conductors therethrough, said conductors emerging in spaced parallel relation;

means for fastening a said strip across said conductors at their point of emergence to mark and maintain said relation; and

means for unlocking said rotors.

positions to render all said 7. Apparatus pursuant to claim 6 wherein said fastening means comprises means for adhering first and second strips to each other with said conductors sandwiched thereinbetween.

8. Apparatus pursuant to claim 7 wherein said strip material is a heat-scalable plastic and wherein said adhering means comprises means for applying heat to said first and second strips.

9. Apparatus pursuant to claim 8, further comprising a comblike member and means for inserting the comb teeth in the spaces between said parallel conductors as they emerge, and for drawing said comb downstream to maintain said conductor parallelism.

10. Apparatus pursuant to claim 8, further comprising means for feeding continuously said strip material along either side of the conductor array emerging from said rotors, and for severing said material afteradherence of a portion thereof to a position across said conductors. 

1. Method for periodically maintaining dissociated threadlike elements in spaced, parallel sequential relation comprising the steps of: drawing subgroups of said elements through respective linear passages in plural rotatably mounted members capable of being lockably positioned to render all said passages planar and parallel; momentarily locking said elements while continuing with said drawing; maintaining said elements planar and parallel for a short distance at their point of emergence from said passages; adhering a flexible strip to all conductors at said point; and unlocking said members.
 2. Method for periodically maintaining all conductors of a group of insulated and variously twisted conductor pairs in spaced, parallel sequential relation comprising the steps of: drawing the conductors of each pair through separate passage pairs in each of a plurality of rotors freely rotatable and capable of being lockably positioned to render all said passages planar, parallel, and of predetermined spacing; momentarily locking said rotors while continuing drawing said conductors therethrough; maintaining said conductors planar, parallel and so spaced for a short distance beyond their point of emergence from said passages; fastening a flexible strip to all conductors at said point; and unlocking said members.
 3. Method of claim 2 wherein said fastening step comprises adhering first and second strips to each other with said conductors sandwiched thereinbetween.
 4. Method of claim 2 further comprising completing said locking step within the time required for the pair with the longest twist length to complete one revolutioN.
 5. Apparatus for periodically applying flexible strips to conductors in a group of twisted pairs comprising: a plurality of freely rotatably mounted rotors for threadably receiving each of the conductors of the respective twisted pairs; means for locking each rotor to orient all threaded conductors in a single plane; means for momentarily extending the conductor portions in spaced, parallel relation and for thereafter applying a flexible strip crosswise at such point; and means for releasing each rotor for resumption of free rotation.
 6. Apparatus for periodically applying flexible strips to tip-ring telephone conductors in a group of twisted pairs, characterized by: a plurality of freely rotatable rotors each with two threadways for receiving the respective conductors of a given pair, a one of each said threadings designated to receive the tip conductor of the given pair; means for drawing the conductors of each pair through said rotors while freely rotating; means for locking said rotors in positions to render all said threadways planar and parallel while continuing to draw said conductors therethrough, said conductors emerging in spaced parallel relation; means for fastening a said strip across said conductors at their point of emergence to mark and maintain said relation; and means for unlocking said rotors.
 7. Apparatus pursuant to claim 6 wherein said fastening means comprises means for adhering first and second strips to each other with said conductors sandwiched thereinbetween.
 8. Apparatus pursuant to claim 7 wherein said strip material is a heat-sealable plastic and wherein said adhering means comprises means for applying heat to said first and second strips.
 9. Apparatus pursuant to claim 8, further comprising a comblike member and means for inserting the comb teeth in the spaces between said parallel conductors as they emerge, and for drawing said comb downstream to maintain said conductor parallelism.
 10. Apparatus pursuant to claim 8, further comprising means for feeding continuously said strip material along either side of the conductor array emerging from said rotors, and for severing said material after adherence of a portion thereof to a position across said conductors. 